Printing ink



Patented Se t. 3,1946

'umren sures "P TENT OFl-ICE v v 2,400.8;81NK

PaulWhymuliaCoi-ona,

No Application July Lo Island, .1, 7 HarryLlnkletten N a Serial No.494.242

This invention relates to printing inks, and is directed particularly ata new type of printing ink, characterized by its very rapid drying whenexposed to-ultra violet light. g

The problem of drying inks rapidly has been before the printing inkindustry for a considerable number of years, in view of the fact thathigh speed printing, combined with high quality. is desired. One groupof investigators has dropped the typical slow drying inks made withdrying oil, and gone to an ink containing a solvent whichissubstantially non-volatile at ordinary temperatures. but which isvolatilizable at tempertures of the order of 150 F.--see GesslerU. S.Patent No. 2,087,190. The use of such inks requires the installation onthe press of heaters to heat the paper, and of exhaust fans to removethe vapors and fumes coming from the printed paper, so that, while theinks have been extremely successiul in large scale printing and in largescale operations, there still remains the desire to provide a quickdrying ink which can be used without the necessity for the installationof large amounts of equipment in connection with any press. a

The quick drying properties of tung oil and other oils containingconjugated systems of double bonds (such as dehydrated castor oil andconjugated linseed oils) have made these oils the principal attackingpoint for investigators interested in producing fast "drying inks forquality printing. It'has been proposed to dry inks made with such oilsas a base by the use of ozone and by the use of ultra violet light.While both 01' these expedients increase the speed of drying of the ink,neither oi them is fast enough to cause the ink to dry sufllciently forhandling within the necessary short time, of the order of seconds.

We have discovered that the speed of drying oi oils and other binderscontaining conjugated double bonds, when exposed to ultra violet light.is enormously accelerated by the inclusion in the composition of a smallpercentage (from about 1 to 10%) of dicinnamal acetone. Inks formulatedfrom oils containing conjugated double bonds and a small percentage ofdicinnamal acetone, in addition to the customary additions, have beendried as on coated non-absorbent stocks with ultra violet light in timesof the order of a few seconds. .1

The use of dicinnamal acetone in inks not containing binders with conigated systems of double bonds does not produce such rapid rying; butsuch inks, when exposed to ultra violet light, dry much more rapidlythan similar inks not containing dicinnarnai acetone. The drying of or-3 Claims. ((1106-48) thod. ypical of our invention are the following:

Example 1.-W0od oil varnish Lithol barium toner 28 Oil varnish 54varnish 18 The oil varnish china-wood oil.

to 6., and add 5% crude di- Then add 5% liquid cobalt The resin varnishis made as iollows:

- Per cent Zinc resinate 47.5

Per cent Solves: (petroleum distillate 0! zero dime yl sulfate value boe 250-270 C.) m rang and smug,

Liquid cobalt dryer 4.75 This ink was printed on a non-absorbent claycoated carton stock, and passed through a tunnel where it was exposed toa source of intense ultra violet light (two mercury vapor quarts lamps);

The length 01' time of exposure in the tunnel was two seconds. The inkcould be handled on removal from the tunnel, and could be backed up byprinting on the other side. almost immediately. Example Z.-Varnish Estergum (glycerol-rosin ester) 50 Rosin Tung oil are heated at 250 isreduced with- C. for 20 minutes; the varnish when made into anink.drying as goodas that of Example 1 is obtained. It should be noted has aconjugated system oi double that rosin bonds, and thus helps to absorbthe ultra violet used, provided they are press-stable, and arerapenergy. idly volatilizable from the iilm at IOU-150 C.

Obviously, extensive changes can be made in Elxample 3'Vami8h v thescope of the examples, without departing from A satisfactory varnish canalso be made from- 5 the scope of the invention, which i defined in thePounds claimsll L We claim: a

0 Lea: gilsinate Z0: A p nting ink characterized by improved I E 1 66drying when exposed to ultraviolet energy, o l l n iii f f 1 7% l0 priing pigment dispersed in a vehicle capable of being dried by ultravioletenergy, and containing The resin andtung oil a h a as in Exama binderhaving a: conjugated system of double ple 2-- bonds, and containing fromabout 1 to 10% of ZZ P G-f h dicinnamal acetone; whereby drying by ultravio- I Pounds let is substantially accelerated.

Zinc resinate- I I 2. A printing ink characterized by improved aredissolved drying when exposed to ultra violfiiia energy, comprisingpigment dispersed in a ve cle capable of Cinnamic alcohol m dried by 1mviolet energy, and consist- The solution is reduced with- I me at le inp f tune oil. andcor tainine from about 1 to 10% offdicinnan al" etizmeY Petroleum solvent as in Example 1 35 g y .7 a whereby drying byultraviolet is sub tially Dicinnamal acetone accelerated. V ilhesevarnishes are used with ordinary pig- 3. A printing ink characterized byments in the normal way to make printing ink. drying when exposed toultraviolet Ordinary oxidation catalysts may be added in prising pigmentdispersed in' a'vehi known manner, as may the various addants widebeingdried by ultra',violet'energy 1y used to control printingcharacteristics; While at least in part of rosin, andijcont mpg we haveshown but one solvent, it has been used about 1 to 10% of dicinnIamalacetqneyw V only because it is representative of petroleum drying byultra violet is,substantially,accelerate solvents which do not undulyattack rubber roll- PA'UL1 WHYZN'U ers. A wide variety of other solventsmay be HARRY

